It is understood that a woman working at the Fairfield Store and Takeaways was confronted by a female offender, believed to be holding a knife.
A police spokeswoman said the offender apparently quickly left the scene. No-one was hurt and there was no damage.
The incident was reported at 8.50pm. It was initially ``not clear what or if anything was taken'', and there may have been some delay in reporting the incident.
Further details, including the nature of any weapon, or a detailed description of the offender, were not available, the spokeswoman said.